Flowering shrubs are planted for their colorful bloom and usually require some pruning each year to maintain their natural shape, and to keep them from growing too large. Never use clippers on deciduous, flowing shrubs. If they have been neglected for many years it is best to prune the oldest and poorest branches back to ground and shorten the others to reasonable lengths to keep the plant from becoming leggy or straggly. It is not good practice to trim all the lower branches and the young shoots coming up around the base of the plant, nor to give the plant a "barber-shop" haircut, rounding off of a shrub until it has the outline of a mushroom or an igloo. This makes it unnatural, reduces it's flowing area and creates an effect that can be corrected only by demolishing the top and starting all over again.
Pruning of shrubs can be done at any time of the year, but there are better times to prune than others. When to prune the shrub depends on whether it is a spring flowering or a summer/fall flowering plant.
Spring flowing shrubs, like the Forsythia, produce bloom on wood grown the previous season. It should be pruned shortly after blooming, to allow new growth of wood for next season's bloom.
Summer/fall blooming shrubs bloom on wood grown during the current season. Prune these shrubs either in the late fall or early spring.
Lilacs have the tendency to grow too tall and become leggy. These plants should be kept down to 6-8 feet in height by removing the old stems periodically and thinning if needed. Old, out of control plants should be cut nearly to the ground and re-started as an entirely new plant.
Hedges have two general classifications. Shrubs or trees planted close together in a row to form an informal hedge, wind break or high screen should be allowed to retain their original form and characteristics. Pruning of this type of hedge is confined to thinning for density and the removal of broken, diseased or dead branches.
The formal hedge on the other hand takes kindly to close, persistent pruning and shaping.
The newly planted hedge will result in a uniform foliage density from top to bottom if properly fashioned from the very beginning. It is a mistake to allow the plants to reach their desired height before pruning. This is usually the reason for so many poor, unsightly hedges with thin sparse branching at the bottom. All hedges should be pruned to be wider at the base than the tops. This is so that the lower branches get plenty of light to retain their foliage.
Pruning of apple trees should be done in late February, after the danger of frost but before the buds begin on the tree. As with flowering shrubs when pruning is done depends on where the tree buds. Trees can have deadwood removed at anytime of time of the year.
Trees in the forest are pruned by other trees with the competition for sunlight, but in the urban setting, the tree health is maintained only by proper professional pruning.
PRUNING PROCEDURE:Never remove more than 1/3 of a tree's crown. Where possible, try to encourage side branches that form angles that are 1/3 off vertical. For most species, the tree should have a single trunk. If a removal of main branches are necessary, but them back to the trunk to avoid leaving stubs. For most deciduous (broadleaf) trees, don't prune up from the bottom any more than 1/3 of the tree's total height.